Sealed gas lasers are employed in a large number of applications because of their compact size, reliability, and relative ease of manufacture. One such laser is disclosed in U.S. Pat. No. 4,805,182, issued to Peter Laakmann (the Laakmann patent), assigned to the assignee of the present invention and incorporated by reference herein in its entirety. The Laakmann patent discloses an all metal sealed gas laser that allows for an inexpensive manufacturing process while achieving excellent performance in laser power and operating efficiency.
A prior art all metal sealed gas laser 10 covered by the Laakmann patent is shown in FIG. 1. The laser 10 includes an aluminum housing 12 containing a laser gas medium, such as carbon dioxide. Within the housing 12 are first and second electrodes 14, 16 having electrode surfaces 18, 20 facing each other across a laser bore 22. Also enclosed within the housing 12 are grounded first and second wall members 24, 26 having wall surfaces 28, 30 that, together with the electrode surfaces 18, 20, surround and define the laser bore 22. Input line 32 is coupled between the first and second electrodes 14, 16 and an RF power source (not shown). The first electrode 14 is coupled to the second electrode 16 by a plurality of coils 34 so as to provide anti-phase excitation of the electrodes.
Although the laser 10 achieves excellent laser power performance, the overall efficiency is less than optimum because of plasma losses to the grounded wall members 24, 26. Such plasma losses are caused by electrons within the plasma re-combining with ions on the wall surfaces 28, 30. The grounded wall members 24, 26 also cause the laser gain to have a different spatial distribution in the horizontal direction than in the vertical direction.